Enquête sur l'usage des matières fertilisantes en agriculture urbaine et périurbaine de Lubumbashi (République Démocratique du Congo)

Abstract

Current practices of fertilizing farmers in the Lubumbashi market gardens are a major constraint in the production of Chinese cabbage (Brassica chinensis L.) in terms of quantity and sanitary quality. In order to improve and promote sustainable practices related to the use of fertilizer materials in Lubumbashi, field research based on interview surveys coupled with observations and analyzes in the soil laboratory as well as Chinese cabbage were made. A first survey targeted 246 producers in six sites between April and June 2016. Next, 50 producers from the previous list were surveyed between April and June 2017 in five sites and in-depth observations were made on soil quality of their plots and the performance of Chinese cabbage production in relation to their cultivation practices. The collected data was entered, saved on Excel file and analyzed using the Minitab 18 software. The results of surveys and observations have shown that the production of Chinese cabbage in Lubumbashi is mainly carried out by men (56%). To produce, farmers plant small areas of 3.6 ± 2.5 ares and occupy 100% of them to produce Chinese cabbage. The variety of Chinese cabbage "Chihili" is the most cultivated. The cultivation of cabbage has several constraints including nutrient deficiencies and pests such as Agrotis ipsilon which is considered the most dangerous. Urban farmers in Lubumbashi share indicators of fertility and soil poverty with scientists and producers in other parts of the world. To fertilize their plots, farmers use the principles of ISFM. They use urea (4.9 ± 2.2 kg / are), NPK (2.4 ± 1.4 kg / are), chicken droppings mixed with chips (38.6 ± 5.4 kg / are), dried chicken droppings (0.6 ± 0.0 kg / are) and composted household waste (0.2 ± 0.0 kg / are). To bring these nutrients, 56% producers combine urea and NPK, 38% combine organic matter, urea and NPK and 6% use only urea. These combinations provide on average 3.47 ± 1.51 kg N / are, 1.19 ± 0.47 kg / are P2O5 and 1.16 ± 0.48 k / are K2O. Urban farmers in Lubumbashi produce on average 690.5 ± 284 kg of Chinese cabbage and obtain a gross product of 374 316 ± 44 020 CDF, that’s mean 258,15 (EUR) per farm and for a production cycle of about 45 days. These farmers pay 70.71% of their money for the purchase of fertilizers. The average labor productivity of the Lubumbashi market gardeners is 1,510.27 CDF (1,042 EUR) per day. In addition to the constraints mentioned above, there are critical overruns of the heavy metal content standards of crops. Compared to these, Chinese cabbage leaves exceeded 202 times the ACPA recommended threshold for Cr, 93.33 times for the Pb threshold and 24.7 times the Cd threshold as set by EU and 10.55 times The Cu threshold fixed by ACPA. A series of ways to improve the situation are proposed.